Al Jazeera is reporting that according to the president in Lebanon, it was almost three thousand tons of ammonium nitrate that blew up https://www.aljazeera.com/news/2020/08/huge-explosion-rocks-... .
Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
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Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#12Unless I'm missing something they forgot to account for the fact that dimensional analysis will only give you a result up to a constant. This should be somewhat obvious as otherwise you'd get a different result with different units (and no SI units won't save you here, those just work for several common equations in physics not ones you came up with yourself).
it's not really dimensional analysis. the same methodology was used to estimate the Trinity blast.
IIRC dimensional analysis lets you put constraints on the form of the equation, by requiring that the variables form dimensionless groups. But you still have to include the right variables, and then measure the values of those dimensionless quantities under different conditions (for instance the Reynolds number for different velocities or length scales) to figure out how the groups scale relative to one another. But I'm sure that data already exists for the situation in question. It would just be a matter of estimating the values from the video and dropping them into the equation.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#13At max 0.2K TNT
What is your evidence or logic for claiming so? Just a bare claim is not very convincing.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#14The media doesn't seem to understand how big this is yet in short and long term damage and loss of life. I guess that doesn't matter? They are more for political bickering now? Running theory Ammonium Nitrate stored at port for many years - https://mobile.twitter.com/HachemYassin/status/1290702640930... [Edit] Skipping the loss of grain and produce in port and the actual port in a country on the brink during a pandem…
What's with "Media"-blaming nowadays, it seems every Tom and Dick expects them to say/do in-depth analysis of everything Tom or Dick wants...
At least the main media I read gets it, e.g.: https://www.theguardian.com/world/live/2020/aug/04/beirut-ex...
On a slight positive side, at least this explosion will mean the rulers of that country can now ask for help without losing face/admitting their failures/corruption...
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#15Wikipedia's page of the largest non-nuclear explosions [1] was already updated and states "It generated a shock-waves equivalent to 13 tonnes TNT". Not sure who made this estimation and how, but various photos on that page can give you an idea what a large explosion looks like. For example take a look at the Yamato explosion [2]. Yamato was a 70000 ton Japanese battleship; the large explosion was due to its magazines…
The ship you can see in the bottom left of the Yamato's explosion (link [2]) is a Japanese destroyer. I'm not sure which ship it is specifically, but she is likely 100-130 meters in length (those were the only ones around at the time Yamato sank). And she's closer than the actual cloud.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#16Unless I'm missing something they forgot to account for the fact that dimensional analysis will only give you a result up to a constant. This should be somewhat obvious as otherwise you'd get a different result with different units (and no SI units won't save you here, those just work for several common equations in physics not ones you came up with yourself).
it's not really dimensional analysis. the same methodology was used to estimate the Trinity blast.
It is dimensional analysis provided you can justify that the constant should approximately be 1. This is what G. I. Taylor did for the fireball of the trinity test. And apparently it does end up being close to 1.
I do worry about the accuracy of this a bit, but looks like it could in theory work.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#17Al Jazeera is reporting that according to the president in Lebanon, it was almost three thousand tons of ammonium nitrate that blew up https://www.aljazeera.com/news/2020/08/huge-explosion-rocks-... .
It's hard to imagine, but that would mean this explosion was nearly 3.5x larger than 2015 Tianjin[1] which was 800 tonnes of ammonium nitrate (336 tons TNT equivalent). The video[2] from Tianjin looked way bigger and apocalyptic, but perhaps just because of the the fireball.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#18A comparable explosion happened in Toulouse, France, in 2001, estimated at 20-40 tons of TNT.
It was also some nitrate storage that blew up. Similar end result, pretty much everything window in the city was blown away, and most of the injuries were caused by broken glass.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#19The media doesn't seem to understand how big this is yet in short and long term damage and loss of life. I guess that doesn't matter? They are more for political bickering now? Running theory Ammonium Nitrate stored at port for many years - https://mobile.twitter.com/HachemYassin/status/1290702640930... [Edit] Skipping the loss of grain and produce in port and the actual port in a country on the brink during a pandem…
What's with "Media"-blaming nowadays, it seems every Tom and Dick expects them to say/do in-depth analysis of everything Tom or Dick wants... At least the main media I read gets it, e.g.: https://www.theguardian.com/world/live/2020/aug/04/beirut-ex... On a slight positive side, at least this explosion will mean the rulers of that country can now ask for help without losing face/admitting their failures/corruption...
It's buried when I go to the Guardians homepage. Might be localised though.
This is real news. I expect it to be easy to see. Not a doomscrolling meaningless repeat of the C19 countdown for the day.
Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT
#20Earlier quoted context omitted.
What's with "Media"-blaming nowadays, it seems every Tom and Dick expects them to say/do in-depth analysis of everything Tom or Dick wants... At least the main media I read gets it, e.g.: https://www.theguardian.com/world/live/2020/aug/04/beirut-ex... On a slight positive side, at least this explosion will mean the rulers of that country can now ask for help without losing face/admitting their failures/corruption...
It's buried when I go to the Guardians homepage. Might be localised though. This is real news. I expect it to be easy to see. Not a doomscrolling meaningless repeat of the C19 countdown for the day.
See, again with the expectations. If every big event requires a link to in-depth analysis on the front page of a news site, they'd need to have a small font size and a 16K monitor... And you'd complain that it's not in the corner you looked.